Rescue workers tasked with pawing through the debris of the mudslide in Washington state face a dirty, discouraging job.

Using everything from heavy equipment and search dogs to their bare hands, rescuers found themselves wading through mud so thick in some areas that geologists say it's like adding hundreds of pounds on each leg.

"They're literally getting stuck, sometimes all the way up to their waist, which means then they need help getting out of that area," Snohomish County Sheriff Ty Trenary said.

Meanwhile, crews are fighting continuous rain, which also brings the deadly threat of another landslide.

"We had a very challenging day today with the rain that further complicated things," Snohomish County District 21 Fire Chief Travis Hots said.

Although the National Guard and more than 200 search crews continue to comb the area where the landslide consumed an entire community, officials caution it's extremely unlikely anyone will be found alive.

So far, 16 bodies have been recovered, eight more may still be trapped in the mud, and more than 100 people remain unaccounted for.

"We believe we've located another eight so we're going to stick with the number of 16 until those others are located and brought back to the medical examiner," The Telegraph quoted Hots.

"They're trying to ping for cell phones for the purposes of finding the bodies of people in the debris," Snohomish County Emergency Department director John Pennington said.

The mudslide hit Saturday morning, destroying some 35 homes in its path.

Chris Jefferds, 45, was home with her 4-month-old granddaughter when the wall of mud came crashing in. Her husband, a volunteer firefighter, was away with his daughter at the time.

"I started to get text messages from people who tried to call her and she wasn't responding. Then it starts to sink in," Kelly Peterson, a friend of Jefferds, recalled.

Authorities say victims may also include non-residents passing through in their cars on nearby state highway 530.

On Wednesday, members of one close knit community held a vigil in memory of those who lost their lives, while praying for miracles that more survivors would be found.

Meanwhile, evidence is emerging that Saturday's mudslide could have been prevented. A 1999 report warned that the area had "the potential for a large catastrophic failure."